1. Field of the Invention
The present invention relates to a treatment solution for ink-jet recording, a water-based ink set for ink-jet recording, an ink-jet recording method and an ink jet recording apparatus.
2. Description of the Related Art
In some cases, ink-jet recording is performed by using a treatment solution in which polyallylamine (PAA) is blended, for the purpose of improving optical density (OD value) of an image recorded with a water-based ink using a pigment. The PAA contained in the treatment solution is capable of causing the pigment in the water-based ink to aggregate on a recording medium, consequently making it possible to improve the optical density (OD value) of the recorded image.
However, in a case that the PAA is singly used as the pigment aggregating agent in the treatment solution, the water-based ink is placed on a surface of the recording medium but is not fixed satisfactorily to the surface, and thus the resisting property against highlighter-pen (highlighter-resisting property) is not sufficient as compared with a case in which the PAA is not used. Namely, the improvement in the optical density (OD value) of the recorded image and the highlighter-resisting property are in a trade-off relationship. On the other hand, the treatment solution for ink-jet recording as described above is also required to have sufficient fluidity after evaporation (after-evaporation fluidity). When the after-evaporation fluidity is not satisfactory, for example, in a case that the treatment solution is discharged onto the recording medium from an ink-jet head, the fluidity is lost after the treatment solution has been left to stand in the ink-jet head for a predetermined period of time and has evaporated, which in turn causes discharge failure. Further, also in a case of applying the treatment solution to the recording medium by a system or method such as stamp coating (application), brush coating, roller coating, etc., there is also a fear that uneven coating might be caused due to the unsatisfactory after-evaporation fluidity, and that a flow passage (flow channel) for the treatment solution in the ink-jet recording apparatus might be closed or clogged.
In view of the above situation, an object of the present invention is to provide a treatment solution for ink-jet recording which is capable of improving the optical density (OD value) of the recorded image and which has excellent highlighter-resisting property and excellent after-evaporation fluidity.